Conventionally, in order to achieve a wearing comfort while preventing the leakage of bodily waste, various efforts have been made for a disposable diaper. For example, various structures are proposed to improve the fitting of the disposable diaper to the hips of the wearer.
In the disposable diaper described in Patent Literature 1, in order to enable a raised portion formed in a rear waistline portion to easily enter the caved portion (anal cleft) of the hips, a structure in which elastic members provided in the rear waistline portion are given an almost V-shape towards the crotch side at the central portion in the product width direction has been adopted.
Furthermore, in a disposable diaper described in Patent Literature 2, in order to make an exterior sheet stretchable in the portions corresponding to the left side of the left hips, the sacrococcygeal portion, and the right side of the right hips in the rear waistline portion of the exterior sheet, a structure in which a plurality of elastic members are provided along the product width direction and at an interval in the product longitudinal direction has been adopted.
However, the aforementioned conventional disposable diaper had the below problems. That is, a problem of the disposable diaper described in Patent Literature 1 is that the raised portion enters the caved portion of the hips, and thus, friction is generated easily between the raised portion and the surface of the skin when the wearer moves his or her body, resulting in a feeling of discomfort being given to the wearer and a stronger stimulation being applied to the skin of the wearer. Another problem of the disposable diaper is that it stretches in the product longitudinal direction as well, and thus a shift in the position occurs easily in the product longitudinal direction, which is likely to result in leakage of bodily waste.
A problem of the disposable diaper described in Patent Literature 2 is that the absorbing portion of the disposable diaper is in close contact with the caved portion of the hips, and thus, a feeling of discomfort is given to the wearer and a stronger stimulation is applied to the skin of the wearer. In addition, in the disposable diaper, elastic members are provided across portions which correspond to the left side of the left hips, the sacrococcygeal portion, and the right side of the right hips, respectively, and thus, the wearer and the disposable diaper are in close contact each other in order to retain bodily waste such as stool. As a result, it becomes difficult to retain the bodily waste in the disposable diaper, thus causing a concern over induction of leakage from the side of the leg hole openings.
Furthermore, the conventional disposable diaper has been designed based on the posture when the wearer stands upright or the posture when the wearer lies on his or her back, and postures unique to infants have not been sufficiently considered. Therefore, the disposable diaper cannot run along the body in the sacral portion of the wearer, easily resulting in a gap between the body and the disposable diaper. Particularly, when an infant adopts a so-called C-shaped curved posture, that is, a posture where the back is curved, such as when the legs are raised or when the infant is held in arms, there tends to cause a problem that the diaper is shifted and a gap occurs around the lower back at the dorsal side.